And lewis v



i kiln is iliade Of too frca.

be no burning or calcnnng action in the-ui.

UNITED STATES PATENT OFFICE.

ARTHUR E. TBUESDELL, 0F EUTLAND, VERMONT, AND LEWIS F. PHILLIPS, OF WEST STOCKBBIDGE, 'MASSACHUSETTS To 11H whom it may com-ern:

Be it known that we, .Karima E. Taurenem, anp] Lnwis l?. PHILLIPS, citizens of the l'nitcd States, residing, respectively, at liutland. county of Rutland, State of Vermont, and West Stockbridge, county of Berkshire7 htate ol Massachusetts, have invented an Improvement in Rotary Kilns, of which the l'ollowiupr description, in connection with the acconipanying drawinpnis a specifica4 tion, like characters on the drawing representing like parts.

This invention relates to rotary kilns and particularly to kilns of this type which are designed for burning lime. Rotary lime kilns ab now commonly made comprise a single cylindrical burning chamber which is set at a slight inclination and is mounted upon two separated bearings, means to feed `the unburnod lime into the upper end of said chamber, and means to introduce Cornhustible gases into the lower end of Vthe chamber. The rotation of the cylindrical chamber causes the lime to gravitate aradaallutr to ward the lower end, and during its morcinent through the chamber, the burning op eration takes place, the products of combustion being delivered to a sta-ck connected to the upper end of the chamber.

lt is a desideratum to make the chamber as long as possible, so that the lime will have a better 'chance to become thoroughly burned while it is traveling from one end to the other of the rotary kiln` but there is a limit to the length which the cylindrical chamber of a rotary kiln can bc made practically, for if said chamber has too great a length, it will not be strong or rigid enough to bc supported properly on two bearings only. and il has been found in practice to be impracticable to use more than two bearings because of the ililiiculty in keeping the bearings in alinement.

cnil of the kiln because as the combustible gases pass upwardly through the kiln. thcv become consumed and eomn'ijnglcd with VU... gas which is delivered from thel burn in; r lunc. and in a long kiln there will be .such an acrumulatio.. ofthe CU, gus at the cud rif-the kiln as 'to prevent any Consequently, heretofore, it has not been doomed practicable to make a rotar) kiln of a greater length than about one hundred and twentyv feet.

upper burnin;r action.

Specification of Letters Patent.

.\loreover, if a rotary f ta length. there wi l atentcd Aug. 24, 1920.

Application ined october zo, 191s. serial 'No 129,139.

One of the objects of our invention is to provide a novel construction by which the length of a rotary kiln can be increased to a considerable extent without involving any of the disadvantageous features above re ferred to.

' We propose to do this by making the kiln in two sections arranged in tandem, each section being independentlyI supported on two bearings, and said sections being provided with a joint between them which permits the limestone to pass freely from the upper section to thc lower sci-tion, while pci`Y iuittinpr sullirient free play between the ser tions so that they will rotate freelv, even though the) arc not entirely in rilinernent. We also propose to provide a` novel means b y which an added Volume of air. prefer ably heated air. can be introduced into the kiln at some point between its ends, this added volume of air (which for convenience we will hereinafter term secondary air) furnishing added oxygen to the gases in the kiln so as to counteract the eliectof the CU2 gas and brovide for continuing combustion through the entire length of the elongated kiln.

ln order to f fii'e an understanding of our inn-nylon. wc have illustrated in the drawY ings a selected embodiment thereof which u ill now be described. after which the novel f'eatirrca will be pointed out in the appended claims.

l"i, urc l shows a kiln embodying our inwiition in vertical section:

Fig. 2 is a section on the liuc 2v2, Fig. l:

Fig. 3 is a section on the lini- VigY l,

Uur improved kiln comprises the upper section l and the lower scr'tlon each in the form ol' an elongated cylindrical chamber. The upper 4section 1 is rotatablyv mounted u ion the tufo bearings 3 and 4 and is pro- `v|ded with the gear as lIsli'al. by which it ma)Y be rotated. The. lower section is mounted on two bearings (i and 7 which are indi-pendent from the bearings 3 and 4, and it is provided with the gear 8 by which it Vmay be rotated. Preferably the gears 8 and ."rwill bc driven from the same source of power so that the two kiln` sections l and 2 Iwill rotate in unison. The'upper end 'of the upper kiln sectionV 1 communicates with ,the

' usual dust chamber 9 havin-,Lr the stach;` 1i) leading thcrcfrom and then unbnrned maurial is;1 fed to the kiln section l through a feeding hopper or chute ll, as usual. `The the npper section is delivered into the lower section. f The lowervend of the lower kiln section .is connected`to a gas producer 12 oi. any

suitable or usual construction which pro duces combustible gases that are delivered to the kiln. The burnt material is dis.. charged from the kiln into an inclined rotatable e Ylindrical chamber 13, as usual in 4rotary ki n's of lthis type.

By making the kiln in two sections l and 2 and providing independent bearings for each section, a longer kiln can be made than would he possible if the kiln was in the form of a single chamber only. The upper kiln Section 1 .can be made practicallyas long as it is possible to make an ordinary kiln,'and the lower kiln ction 2 can be m'ade as long as desirable, thus `adding to the-total length of the kiln. Since these kiln sections are independent from each other and are sustained in independent bearings, and since the joint between the upper end of the kiln section 2 and the lower end of the kiln section 1 allows of a certain amount of play, the operation of the kiln will not be affected at all, even though the two kiln sections arej not in absolute axial aliuement. By thus making the kiln in two sections, it is possible to build a practical kiln of considerably increased length. The increase in length adds to the time which it takes for the material to travel through the kiln, and thus gives added time for the burning operation.

Yil'hcre the length o the kiln is thus increased, it is desirable that an added quantity of air should be introduced into the kiln at some point between its ends so as to sup-` port combustion at the upper end of the kiln. Ve accomplish Athis herein by providing the lower kiln section 2 with a Jacket 14 which forms with said lower kiln section a chamber l5. The lower end of the chamber l5 is open to the atmosphere at 1G.' The jacket 14 extends beyond the up )er end of the lower kiln section 2 and is iormed with the inturned Flange 1T which engages the upper kiln section 1. A space 18 is provided between the upper and lower' sections which afords communication between the chamber 15 and the interior of the kiln. With this construction air will enter the chamberl at 16 and will become heated therein by contact with the walls ot the kiln suction 2, and the heated air will be delivered through the Space 18 into the kiln at a point between its ends. This added air (which we have termed secondary air because the air which is admitted with the combustible gases at the lower end of the kiln section 2 constitutes the primary air) supports combustion in the upper end of the kiln so thatI notwithstand ing the fact that considerable (,)O gtisvis given oil' from the burning lime tilereewill be a sufficient supply of oxy en in the upper end of the kiln to insure to complete combustion ofl all the combustible fas i Irodueed at the lower end of the kiln. he full benelit of all the combustible gas is thus obtained and burning of the lime is accomplished without any combustible gas being wasted. By means ofthe increased or lengthend burning arca a more uniform tproduct can be produced and a larger quentlty of material can be burned in a given time than is os sible with the rotary kilns vas hereto ore constructed.

Having fully described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a rotar kiln, the combination with a rotatable cylindrical burning chamber, of means to deliver combustible gas and pri mary air to the lower end of said chamber, a jacket surrounding a portion of said cham ber and open at one end to the atmosphere, arid means constituting a communicatiori between the other end of said jacket and the burning chamber at a point intermediate of its ends whereby heated secondary air will be delivered tosaid burning chamber.

2. ln a rotary kiln, the combination with upper and lower,A kiln sections,`each inde pendently supported for rotative movement the lowerend of the upper kiln section and the upper end of the lower kiln section being separated to form an air inlet, and means to suppl heated secondar4 air to said 'nlet.

3. .n a rotary kiln, t e combination with upper and lower kiln `sections arranged iu 'alinement with each other, and each inde pendently sup orted for rotative movement,

of means to f eliver combustible gus to the lower end of the lower section vand a jacket surroundin i the lower Ysection and open to the atmosp ere, said jacket c mmunicating with the kiln at the upper en of theilower section whereby heated air will be delivered from thc jacket to the kiln intermediate of its ends.

4. In a rotary kiln, the combination with upper and lower kiln sections, each independently supported for rotative movement and arranged to provide a space between thc lower end of theupper kiln section and thH upper end of'the ower kiln section, and jacket surrounding the lower kiln sectie and communicating with said space wherein heated secondary air is furnished to the kiln between. said sections.

In testimony whereof we have signed ou names to' thisspecification.

ARTHUR E. TRUESDELL. LEWIS F. PHILLIPS.

l! Ii 

